Radio frequency identification (RFID) technology was developed in the middle of the 20th century and has drawn attention since it was used for stock management and supply chain management at the end of 1990. RFID is a method of identifying individual products using frequency.
FIG. 1 illustrates a conventional RFID system 100. The RFID system 100 includes a tag 10, an RFID device 20, and a host 30. The tag 10 is attached to a product and stores predetermined data. The RFID device 20 is connected with the host 30 (e.g., a personal digital assistant (PDA) or a mobile phone) for data communication and identifies the tag 10 using RF communication.
The RFID device 20 may include a microprocessor having a built-in universal asynchronous receiver/transmitter (UART) for the data communication with the host 30. Generally, the RFID device 20 includes a power supply (e.g., a battery) independent of the host 30 and tends to be miniaturized and mobilized. Therefore, it is desired to reduce power consumption of the RFID device 20 by controlling power supply to elements of the RFID device 20 when the RFID device 20 is not connected with the host 30 or when the RFID device 20 does not need to communicate with the host 30 in more than a predetermined period of time.